U.S. Publication No. 2009/0217833, incorporated by reference, discloses a pitch changing device. The pitch changing device includes an upper roller mounted on an upper axle, a lower roller mounted on a lower axle, the upper and lower rollers forming a roller nip and a motor driving the upper and lower rollers in opposite directions. The motor has an electronic cam velocity profile designed to increase or decrease pitch of the printed products by increasing or decreasing the velocity of the printed products, respectively.
U.S. Pat. No. 6,572,097, incorporated by reference, purportedly discloses a signature slow-down section in a folder of a printing press for slowing down signatures. The folder is driven by a folder drive mechanism. The signature slow-down section includes a frame, a slow-down mechanism supported by the frame and a motor connected to the slow-down mechanism for rotatably driving the slow-down mechanism separately from the folder drive mechanism.
Offset couplings, elliptical gears, planetary gear devices and Schmidt couplings are used to connect shafts that may be misaligned or are not collinear. However such devices may not be industrial enough to withstand the demanding requirements of the eccentric tube style slow downs or requirements of current folders
U.S. Publication No. 2012/0193859, incorporated by reference, includes a drive for a pitch changing device and/or slow down device which is an improvement of the foregoing designs. This orbiting cam drive mechanism includes a first input member rotating in a first direction about a first axis, a second input member concentric with the first input member and rotating in a second direction about the first axis. The second direction is opposite to the first direction. The drive mechanism also includes a plurality of cams connected to the second input member and an orbiting output member. The orbiting output member rotates about a second axis and orbits about the first axis. The second axis is connected to a point on the first input member; the second axis rotates about the first axis. The drive mechanism further includes a plurality of cam followers connected to the orbiting output member and contacting the plurality of cams, the plurality of cam followers rotating about the second axis in the second direction.
Although this orbiting cam drive mechanism is an improvement over prior systems, there is still a need for a lower inertia, more robust pitch changing design that fits into a smaller area while still satisfying a need for higher frequency and faster speeds.